1. Field of the Invention
The present invention relates to integrated circuits, and particularly to a method for programming one-time programmable (OTP) memories of an integrated circuit (IC).
2. Description of the Related Art
Currently, a conventional integrated circuit for measurement includes an analog digital converter (ADC), a micro control unit (MCU), a system memory, and so on. Furthermore, the MCU includes a random access memory (RAM), a central processing unit (CPU) and a programmable interface, etc.
When an integrated circuit is utilized in measuring devices, sensors for measuring pressures or weights are receiving measuring signals. The sensors convert the measuring signals to electrical signals, such as voltage signals or current signals. The electrical signals are converted into digital signals by the analog-to-digital converter of the integrated circuit. And then, the digital signals are computed, processed or further converted by the MCU, and are displayed on an external display. The MCU computes, processes or further converts the signals by an instruction set stored in the system memory. The total and order of the instructions construct a program.
However, in the above utilizations, many of the integrated circuits having an analog-to-digital converter must perform a proofreading process before displaying an accurate measuring value. In the proofreading process, a standard measuring object having standard values is used. A sensor communicates with the standard measuring object to send out a standard signal. The standard signal is converted to a digital signal used as a standard value to be stored in the memory. When the MCU performs a normal measuring program, the standard value is taken out to compute an actual measuring value according to a measuring signal. After the proofreading process, a proofreading coefficient is produced correspondingly. The proofreading coefficient must be stored and can be read by the MCU, so that the MCU can accurately perform a computation or a convertation to obtain an accurate value. Therefore, most of electrical elements require an electrically erasable programmable read-only memory (EEPROM) to store the proofreading coefficient.
However, an additional burner is needed to write the proofreading accurately in the EEPROM. After the step of writing, the EEPROM is taken out from the burner and is communicated with an electrical measuring device of a terminal system to finish the proofreading process.
Generally, when the standard value is stored in a peripheral memory, the MCU stores the standard value in the peripheral memory via a programmable interface. The peripheral memory storing the standard values will increase a cost of an integrated circuit and complicate a configuration of the integrated circuit, such as increasing a serial interface. Furthermore, an instruction set must be stored in a system memory to be read and performed by the MCU. Generally, the system memory still has a large unused space after storing the instruction set, and thus, the unused memory will be wasted.
What is needed is to provide a method for programming a one-time programmable memory of an integrated circuit with a simple proofreading process and a low cost.